1. Field of the Invention
This invention relates to an elastomeric coating and more particularly to a pressurized aerosol composition with elastomeric properties dissolved in a common solvent that is nonflammable, together with a compatible liquefied, normally gaseous propellant.
2. Description of the Prior Art
Methods of repairing stress cracks in interior walls using spackling or joint compound are well known in the prior art. Because the spackling or joint compound used in these methods is inflexible when dried, cracks tend to reappear, often within a few months.
More recently, products designed to resist the reoccurrence of repaired cracks in interior walls have appeared. These products have included a solvent-based liquid coating applied in two coats to a fiberglass mesh tape which requires about four hours of drying time. Another such product is a paste which has a higher degree of flexibility than either spackling or joint compound but which, like them, must be sanded when dried and which will eventually crack, albeit in a year or so.
A combination scratch filler and primer which can be sprayed in very heavy films onto a substrate surface is taught by Kendall in U.S. Pat. No. 4,372,991. These very heavy films are employed to actually fill holes and depressions a quarter inch deep. When dried, the films have very low elasticity and can be sanded to an extremely glossly surface.
Very viscous, heavy bodied elastomeric materials which resemble glue, on the other hand, have been used on exterior surfaces such as roofs both to fill cracks and prevent their reoccurrence, all in one operation. These elastomeric materials, which do not spray well, are typically applied with a brush or roller and dry as a thick, visually obtrusive film.
As far as the applicant is aware, attempts to provide a method of covering previously filled stress cracks in interior walls by dispensing a liquid aerosol which, when dry, forms an adhesive film capable of being stretched twice its original length over a previously repaired crack in drywall, plaster and the like are non-existent in the prior art.
Nor does the prior art suggest a suitable composition for a liquid aerosol from which to produce an adhesive, elastic, paintable film. Indeed, materials such as silicone or urethane formulations widely used in caulking applications and well known for their property of exhibiting long-lasting elasticity and a high degree of adhesiveness are not paintable; and certain paintable caulking materials when dried in thick-bead form tend to crack readily.